Do you have multiple sound outputs? Most video cards, laptops included, have an HDMI output which may have been selected while the laptop was plugged into a TV or external monitor.
Is the sound muted? Does the volume icon even show up on the taskbar (it won't if there's no active sound devices).
Do you have a headset set up for Skype or online gaming? Make sure it's not selected as the default Playback Device.

Ryan D

September 5, 2014 at 11:27 am

In Win7, you can disable sound outputs and they won't show up in the list of available sources until you enable it. To see if this is the case, click the link to view disabled sources (where your sound inputs are normally listed)